A projectile is launched upward at an angle of 75 from the horizontal and strikes the ground a certain distance away. For what other angle would it have the same range?

The range of a projectile is proportional to sin A cos A. If you change the launch angle (A) to its complement (15 degrees in this case), you get the same result.

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To find the angle at which the projectile would have the same range, we need to understand the concept of range in projectile motion.

The range of a projectile is the horizontal distance it travels before hitting the ground. In this case, the projectile is launched upward at an angle of 75 degrees from the horizontal. Let's denote this angle as θ.

To calculate the range, we can use the following formula:

Range = (Initial velocity^2 * sin(2θ)) / g

Where:
- Initial velocity is the initial speed at which the projectile is launched.
- θ is the launch angle.
- g is the acceleration due to gravity.

Since we want to find the angle at which the range is the same, we can set the range equations for both angles equal to each other and solve for the unknown angle. Let's call this unknown angle α.

Range(75°) = Range(α)

Using the range formula, we have:

(Initial velocity^2 * sin(2θ)) / g = (Initial velocity^2 * sin(2α)) / g

The initial velocity and g cancel out, simplifying the equation to:

sin(2θ) = sin(2α)

To find the angle α, we can take the inverse sine of both sides:

2θ = sin^(-1)(sin(2α))

Next, we divide both sides by 2:

θ = (1/2) * sin^(-1)(sin(2α))

This equation gives us the relationship between the launch angle θ and the angle α at which the projectile would have the same range.

To find the specific value for α, we need the value of θ. Please provide the launch angle θ, and I can help you calculate the angle α.